The future Bidadari estate will lay claim to a unique feature - Singapore's first underground service reservoir built on low, instead of high, ground.
Holding enough water to fill three Olympic-size pools, the tank will be built beneath the town's planned park to save on surface space and keep the surroundings unmarred.
The land above it will be "integrated with the surrounding park amenities, hence optimising land", PUB said yesterday, adding that high ground available for service reservoirs is "limited".
The Bidadari reservoir could pave the way for more such underground tanks on low ground.
"Where possible, PUB will work with other agencies to explore a similar concept in other new areas," said the national water agency's spokesman.
Service reservoirs store drinking water to regulate supply to homes and boost water pressure during periods when demand is high.
There are 14 such reservoirs now, but all are located on high ground such as Mount Faber and Fort Canning, letting gravity do the work in channelling the water to homes.
In contrast, the Bidadari reservoir will have a pumping station on a 200 sq m plot of land atop it.
Experts The Straits Times spoke to said such a system is viable, given how Housing Board flats already have low-level water tanks, although on a smaller scale.
A lot will depend on the pumping system. It has to be extra reliable in Bidadari, which will have 10,000 public flats.
The estate's first Build-To- Order flats will be launched for sale in 2015.
Work on the reservoir will likely begin in early 2017, alongside general construction work there.
National Research Foundation water technology adviser Lui Pao Chuen, a former Ministry of Defence chief defence scientist, believes that building below the surface is key for Singapore, given the scarcity of land here.
"Instead of having reservoirs above ground, which is water you can't even swim in, you have land that you can walk on. Going underground is an obvious solution to preserve as much free space for people as possible," he said.
The use of below-ground spaces was put in the spotlight by National Development Minister Khaw Boon Wan earlier this month, when he blogged that the Government was considering an underground masterplan.
In the wake of the revelation, experts noted that building beneath the ground is expensive, especially if rock and soil formations are unsuitable.
PUB said yesterday that it was "premature to estimate the cost" of the proposed reservoir as a detailed study on its structure and construction methods has not yet been done.
The reservoir, however, will occupy less than a hectare of space - about a tenth of the park, which will include a man-made lake.
The Straits Times understands the raw-water lake will be separate from the service reservoir, which will hold treated drinking water.